1. Field of the Invention
This invention relates to an electrically operated, by means of a battery, power assist apparatus for a bicycle and more particularly, to a new and novel construction of that power assist apparatus for a bicycle.
2. Description of the Prior Art
Electric powered bicycle have long been known. All electric powered bicycles incorporate an electric motor which is powered by a battery. One way the bicycle is powered is by a motor that operates through a drive wheel which frictionally engages with a support wheel of the bicycle. Movement of the drive wheel adds power to the manual movement of the bicycle or could be the only source of movement of the bicycle. Frictional engagement between the drive wheel and a support wheel is only one method. Others involve many configurations of direct drive involving shafts, chains, and gears but with the common feature of the driving motor being mounted on the bicycle frame in one position or another (e.g., near the pedaling sprocket, on one of the stays or on a rack above the rear support wheel).
The prior art direct drive power assist devices for a bicycle have generally required complex gearing arrangements. Upon removal of the wheel for maintenance, such as tire repair, precise reengagement is difficult leading to excessive wear and noise during operation. Also, complex gearing arrangements are difficult to maintain in precise alignment when the bicycle encounters road bumps and holes. Also, incorporation of prior art power assist apparatuses on bicycles has made it difficult to remove and replace the wheel(s) of the bicycle for tire repair and/or replacement. Additionally, if it is desired to use the bicycle as a normal bicycle and have the bicycle not carry the extra weight of a battery pack plus a motor assembly, the prior art direct drive power assist apparatuses for bicycles have not been designed to be readily removable from the bicycle to permit normal manual usage without the extra weight involved.
In prior art direct drive systems, the motor is mounted on the bicycle frame. Therefore, when the wheel is removed and replaced on the frame, such as required in order to change a tire or to do other types of maintenance, slight variations prevent precise realignment between the drive gear of the motor and the drive gear mounted on the wheel. These slight variations often result in excessive noise and wear.
The subject invention is a power assist apparatus for a bicycle which utilizes a direct drive mechanism between an electric motor and a drive gear, pulley or sprocket mounted on the hub of one of the wheels of the bicycle. It has been found to be most desirable to have the axis of the rotatable shaft of the motor parallel to the rotational shaft of a wheel for reasons of simplicity and smoothness of operation. A one-way clutching mechanism is to be mounted between the wheel and the motor. One or more batteries mounted within a battery pack are to be used to power the motor with this battery pack to be removably mounted on the frame of the bicycle. The motor is mounted within a motor housing with the motor housing being mounted within an enlarged hole formed within a mounting plate. The mounting plate is to be carried by a support wheel of the bicycle with either support wheel being satisfactory. This mounting plate is to be affixed by a bolt fastener (or pin) to the frame of the bicycle. This bolt or pin is to be easily removable. The mounting plate can be attached at any desired angular position on the support wheel but when selected is then fixed. The motor housing may be removably mounted on the mounting plate by a series of locking tabs being utilized to facilitate the engagement and disengagement of the motor housing to that mounting plate.
The primary objective of the present invention is to provide a vehicle of transportation for work and recreation that can be used by most people without adding to the smog caused by combustion engines, especially in urban areas.
Another primary objective of the present invention is to obtain a self-contained drive train support wheel configuration which, at all times, retains precision alignment between the gear attached to the drive motor and the driving gear attached to the axle of the bicycle. This is critical both for removal of the support wheel for repair and reengagement with bicycle frame to prevent any slight misalignments which cause excessive gear wear and noise.
A further objective of the present invention is to construct a power assist apparatus for a bicycle which is composed of few parts, is of lightweight construction, is efficient, is durable and requires a minimum of maintenance, and still can be manufactured economically.
Another objective of the present invention is to construct a smoothly operating, substantially vibration free, direct drive, power assist apparatus for a bicycle.
Another objective of the present invention is to construct a power assist apparatus for a bicycle which does not interfere with the maneuverability of the support wheel on which it is mounted in order to permit normal tire repair and replacement.
Another objective of the present invention is to construct a power assist apparatus which can be readily removed from the bicycle so that the bicycle can be manually operated in a normal manner when so desired without carrying the extra weight of the power assist apparatus.
Another objective of the present invention is to construct a power assist apparatus which is reengaged with precision indexed alignment between the gears when the support wheel is remounted on the bicycle.
A further objective of this invention is to obtain a practical direct drive gear system employing precision indexing and alignment which is in a self-contained bicycle rear wheel assembly that features: (1) precision alignment with repeated removal and reengagement of rear wheel for repair; (2) maintaining precision alignment in all rough environments; and (3) has fast conversion of non-electric to electric configuration ( less than 3 minutes) and back again with minimal weight penalty in normal operation.
A further objective of the present invention is that the bicycle can be used interchangeably with a regular support wheel or a xe2x80x9cpower wheel.xe2x80x9d The power wheel contains the motor and the gear assembly whereas the regular wheel would be void of both the motor and the gear assembly. When the bicycle is used with the regular wheel, a common type of manually operated bicycle is obtained. When the bicycle is used with the power wheel, the power assist apparatus of the present invention is used to assist in powering of that bicycle.